In general, actuators are devices that convert one form of applied power to a usable form of power that often provides motion of an output element. Various types of actuators may be used in may different types of applications and may include hydraulic, pneumatic, and electro-mechanical actuators (EMAs). An EMA is one type of actuator that includes an electric motor and one or more drive train components to transfer and/or convert power provided by the electric motor to an output element.
EMAs and other types of actuators have a finite service life, which typically ends with the complete failure of the actuator or a partial failure of the actuator that is cost-prohibitive to repair. In some applications, the failure of an actuator during operation may not be catastrophic. For other applications, however, it may be highly undesirable or catastrophic for an actuator to fail while it is being used. In aerospace applications, for example, the sudden or catastrophic failure of a flight control actuator system may have life-threatening results.
Certain conventional approaches have been developed for predicting the remaining service life or imminent failure of an actuator system. These conventional approaches typically involve measuring the elapsed time of operation for a particular actuator in its operating environment. When used in certain applications, for example in industrial applications in which the load conditions for the motor are substantially fixed and occur in substantially uniform intervals or time periods, the elapsed time of operation can be a relevant indicator of the remaining service life and service needs for the actuator system.